Police are on the hunt for a man who sucker-punched a 76-year-old New York woman in East New York.
Yvonne Small was attacked from behind at around 11:35 a.m. on Friday while walking on Alabama Avenue, and is believed to be the latest victim in the sometimes deadly "knockout game," police say.
The attack occurred shortly after a nearby rally held by activists condemning the violent "game" ended. A male suspect fled the scene and Small was taken to Brookdale Hospital, where she was treated for a head injury and later released.
According to the New York Police Department, there have been at least nine other attacks in the city linked to the knockout game, in which perpetrators pummel innocent, unsuspecting victims, hoping to render them unconscious with one punch.
On Nov. 22, police charged one man for punching a 24-year-old Jewish man. In response to that attack in Brooklyn, New York City Councilman David Greenfield told ABC station WABC-TV in New York that officials should send a message of "zero tolerance."
"That's why I called on the NYPD and District Attorney's Office to literally throw the book at these individuals and to charge them with many crimes, including hate crimes and gang assault, because that's what it is," Greenfield said.
Police said there have seven other similar attacks in Brooklyn and believe the motive may be related to anti-Semitism. The NYPD's hate crimes task force is investigating the cases. It was not clear whether the latest victim, Small, is Jewish like all of the nine other victims before her.
Republican state Assemblyman Jim Tedisco has proposed a bill that would classify knockout game attacks as gang assaults, and would require that youths who participate in such attacks be tried as adults, facing prison terms of up to 25 years.
"These twisted and cowardly thugs are preying on innocent bystanders and they don't care if the victims are young, old, a man or woman," Tedisco told The Associated Press when he announced the bill. "Life isn't a video game. These are real people whose lives are not only being put in jeopardy but in many cases destroyed."
But despite increased police crackdowns on the alleged perpetrators, the dangerous game appears to be spreading further throughout the country.
One unidentified Denver man told ABC News affiliate KMGH-TV in Denver that he was sucker-punched when leaving a bar, which would make him one of the first people in that city to be a victim of the "knockout" game.
In Washington, two people were randomly punched in separate incidents but suffered only minor injuries and did not lose consciousness, while two similar assaults in Philadelphia also have police on alert.
In September, Ralph Santiago, 46, of Hoboken, N.J., died from injuries resulting from a suspected knockout attack that sent him careering backward into a fence, where his head got lodged. Three teens -- two 13-year-olds and a 14-year-old -- have been charged with murder.
In late May, two teenagers admitted to fatally beating and killing a man in Syracuse, N.Y. They admitted that the attack began with the intention of knocking out the victim, Michael Daniels, with a single blow. Both teens, 16 and 13, were sentenced to 18 months in jail.
And earlier in May, Elex Murphy, now 20, was sentenced to life in prison plus 25 years in St. Louis for killing a Vietnamese immigrant as part the game in 2011.
Surveillance footage has also gone viral of another attack from 2012, in which a 50-year-old Pittsburgh, Pa., English teacher named James Addlespurger is struck and falls limply to the curb.
Experts say the violent acts appear to be driven in part by a pack mentality and peer pressure put on the perpetrators.
"These kids have effectively de-humanized others," Former FBI special agent Brad Garrett told ABC News. "They are being drastically influenced by the groups to commit the acts."
"This I believe is a real economic issue where those who have nothing feel that they have nothing to lose," said Dr. Jeff Gardere, a psychologist and assistant professor at Touro Graduate School of Psychology in New York City.
"Not only do they get a thrill out of doing something so horrific but then they get to watch it," Gardere said. "Then they get the positive reinforcement of people just watching these videos and these videos, no pun intended, getting hit after hit after hit after hit and these kids are finding some sort of immortality by their bad behavior."
ABC News' GILLIAN MOHNEY, DAN HARRIS, BRANDON BAUR, CANDACE SMITH and The Associated Press contributed to this report.